The Applicant has developed a range of Memjet® inkjet printers as described in, for example, WO2011/143700, WO2011/143699 and WO2009/089567, the contents of which are herein incorporated by reference. Memjet® printers employ a stationary printhead in combination with a feed mechanism which feeds print media past the printhead in a single pass. Memjet® printers therefore provide much higher printing speeds than conventional scanning inkjet printers.
Paper jams are a perennial problem in sheet-fed printers. In a sheet-fed printer, a media feed mechanism typically has an array of roller assemblies and sheets of print media (e.g. paper) are handed off from upstream nips to downstream nips along a media feed path. Small misalignments or variations in speed can cause paper to jam and buckle between rollers, and printing must be stopped until the jam has been cleared. Paper jams are frustrating for users and typically require manual intervention to clear the jam. The printer housing must be opened, the area of the jam identified and the jammed paper pulled from the printer. Invariably, the paper sheet is jammed in the nip of a roller assembly and it is usually necessary to release the nip so that the paper can be pulled easily from the printer. Various mechanisms exist for releasing nips in printers to facilitate clearance of paper jams.
Most printers have a series of roller assemblies upstream of a print zone and these roller assemblies are a common source of paper jams. For example, a de-skew roller assembly may be positioned upstream of a drive roller assembly, and paper jams may occur in the de-skew roller nip, the drive roller nip or both. In prior art systems, each roller nip has a dedicated nip release mechanism. However, it is inconvenient for users to operate separate nip release mechanisms when the source of the paper jam may not be known.
It would be desirable to simplify the procedure for clearing paper jams in printers. It would be particularly desirable to provide a nip release mechanism, which users can operate to release paper from more than one roller nip.